Cryptography – Video cryptography – Copy protection or prevention
Reexamination Certificate
2000-11-15
2002-09-10
Barron, Jr., Gilberto (Department: 2132)
Cryptography
Video cryptography
Copy protection or prevention
C380S201000, C713S193000
Reexamination Certificate
active
06449366
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical disk, an optical disk barcode forming method, an optical disk reproduction apparatus, a marking forming apparatus, a method of forming a laser marking on an optical disk, and a method of manufacturing an optical disk.
2. Related Art of the Invention
In the manufacturing process of optical disks, it has been commonly practiced to record a serial number, lot number, etc. on each optical disk in the form of a barcode.
Since such information cannot be written to a pit information area of the optical disk, it has been practiced to write the barcoded information to a non-information area, or unused space, on the optical disk.
When reproducing (playing back) such an optical disk, the pit information is read by an optical pickup; to read the barcoded information such as a serial number, etc. recorded in the non-information area, however, a separate reading device has been used.
In the above prior art optical disk, since information carrying a serial number and the like is not recorded in a pit area but recorded in a non-information area, as described above, a separate reading device has had to be provided in addition to the usual optical pickup, the resulting problem being increased complexity of the playback apparatus construction.
SUMMARY OF THE INVENTION
In view of the above problem with the prior art, it is an object of the present invention to provide an optical disk wherein data such as a disk ID number, etc. is converted into a barcode and recorded in a pit area in overwriting fashion, thereby permitting the use of a single optical pickup to read both the bit data and barcode data. It is another object of the invention to provide a barcode forming method, etc. for such an optical disk.
One aspect of the invention is an optical disk on which data is recorded with CLV, wherein, in a prescribed region of a pre-pit signal area on said disk, all or part of a barcode is written in overwriting fashion by selectively removing a reflective film in said prescribed region.
Another aspect of the invention is an optical disk according to the first invention, wherein a control data area is provided for holding therein physical feature information concerning said optical disk, and an identifier for indicating the presence or absence of said barcode is recorded in said control data area.
Still another aspect of the invention is an optical disk according to the second invention, wherein a guard-band area where no data is recorded is provided between said control data area and said prescribed region of said pre-pit signal area.
Yet another aspect of the invention is an optical disk according to the first invention, wherein said barcode is formed in such a manner that two or more barcode signals cannot occur within one prescribed tire slot.
Still yet another aspect of the invention is an optical disk according to the first invention, wherein said barcode contains data at least including ID information uniquely given to said optical disk.
A further aspect of the invention is an optical disk according to the 5th invention, wherein said barcode contains data including, in addition to said ID information, a public key of a public key encryption function corresponding to said ID information, said public key is used to encrypt prescribed data, and the encrypted prescribed data is transmitted transmission to an external party in order to obtain from said external party a password required to reproduce said optical disk.
A still further aspect of the invention is an optical disk according to the 5th invention, wherein said ID information is encrypted or applied a digital signature to.
A yet further aspect of the invention is an optical disk according to the 7th invention, wherein a secret key of a public key encryption function is used when applying encryption or a digital signature to said ID information.
A still yet further aspect of the invention is an optical disk according to any one of inventions from first to 8th , wherein said optical disk is constructed from two disk-substrates laminated together.
One aspect of the invention is an optical disk barcode forming method wherein pulsed laser light from a light source is made into a rectangular beam pattern by using a rectangular mask and said rectangular beam pattern is focused on a reflective film in a pre-pit signal region in a prescribed radius portion of an optical disk on which data is recorded, and at the same time, said optical disk is rotated, thereby forming a plurality of rectangular reflective-film-removed regions as a barcode in the same radius portion on said reflective film.
Another aspect of the invention is an optical disk barcode forming method according to the 10th invention, wherein said optical disk includes a control data area for holding therein physical feature information concerning said optical disk, and an identifier for indicating the presence or absence of said barcode is recorded in said control data area.
Still another aspect of the invention is an optical disk barcode forming method according to the 11th invention, wherein said barcode is formed in such a manner that two or more barcode signals cannot occur within one prescribed time slot.
Yet another aspect of the invention is an optical disk barcode forming method according to any one of inventions from 10th to 12th, wherein said optical disk is constructed from two disk-substrates laminated together.
Still yet another aspect of the invention is an optical disk reproduction apparatus wherein recorded contents of a recording area, recorded by forming pits on an optical disk, are reproduced by using a rotational phase control for a motor, while recorded contents of a different recording area than said recording area, recorded by selectively forming low-reflectivity portions on a reflective film in said different recording area, are reproduced by using rotational speed control for said motor, and
the recorded contents of said main data recording area and the recorded contents of said different recording area are both reproduced by using the same optical pickup.
A further aspect of the invention is an optical disk reproduction apparatus according to the 14th invention, wherein tracking control is not performed in said different recording area.
A still further aspect of the invention is an optical disk reproduction apparatus according to the 14th invention, wherein tracking control is, in effect, performed in said different recording area.
A yet further aspect of the invention is an optical disk reproduction apparatus according to the 16th invention, wherein a rotational speed is the rotational speed that would be achieved in said different recording area if said rotational phase control were applied.
A still further aspect of the invention is an optical disk reproduction apparatus according to the 14th invention, wherein the rotational speed of said motor in said rotational speed control is maintained at a prescribed value based on a result obtained by measuring a minimum-length pit in said different recording area.
A yet further aspect of the invention is an optical disk reproduction apparatus according to the 14th invention, wherein said low-reflectivity portions are a barcode formed by selectively removing said reflective film.
A still yet further aspect of the invention is an optical disk reproduction apparatus according to the 14th invention wherein
said low-reflectivity portions are a barcode, and said different recording area is also such area to which contents are recorded with pits,
when reproducing the recorded contents of said different recording area, a high-frequency-component signal generated during reproduction of said pits is which are formed in said different recording area reduced or eliminated by a low-pass filter, thereby making it possible to separate a signal which is reproduced from said barcode.
One aspect of the invention is an optical disk reproduction apparatus according to the 14th invention, wherein
said low-reflectivity portions are a barcode, a
Gotoh Yoshiho
Koishi Kenji
Moriya Mitsuro
Oshima Mitsuaki
Tanaka Shin-ichi
Barron Jr. Gilberto
Kabakoff Steve
Matsushita Electric - Industrial Co., Ltd.
Ratner & Prestia
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